Leviticus 16:29-34

“This shall be a permanent statute for you: in the seventh month, on the tenth day of the month, you shall humble your souls and not do any work, whether the native, or the alien who sojourns among you; for it is on this day that atonement shall be made for you to cleanse you; you will be clean from all your sins before the LORD. It is to be a sabbath of solemn rest for you, that you may humble your souls; it is a permanent statute. So the priest who is anointed and ordained to serve as priest in his father’s place shall make atonement: he shall thus put on the linen garments, the holy garments, and make atonement for the holy sanctuary, and he shall make atonement for the tent of meeting and for the altar. He shall also make atonement for the priests and for all the people of the assembly. Now you shall have this as a permanent statute, to make atonement for the sons of Israel for all their sins once every year.” And just as the LORD had commanded Moses, so he did.